1. Field of the Invention
The invention pertains to a paste composition, a green sheet, for forming a dielectric layer, and a method for forming a dielectric layer of plasma display panel, and the dielectric layer can be formed by a simple process using a green sheet containing an optimized paste composition.
2. Description of the Related Art
Plasma display panels (PDPs) are flat panel display devices that can display images or information by using the light-emitting phenomenon of plasma discharge PDPs generally are divided into DC-types and AC-types according to the panel structure and driving method. PDPs generate visible light obtained from the energy difference when ultra violet light, which is generated by the plasma discharge of a gas (such as He, Xe, etc) provided in each cell, excites a phosphor lining in the cell, which emits a visible photon when returning to the ground state.
The above mentioned PDPs have advantages such as easy manufacturing, simple structure, high brightness, high luminous efficacy, memory capacity, and a wide viewing angle over 160°. PDPs also can be used for wide screens of 40 inches or more.
The structure of a PDP generally includes an upper substrate and an oppositely disposed lower substrate, walls, and cells formed by the two substrates and walls. Transparent electrodes are formed on the upper substrate, and bus electrodes are formed on the transparent electrodes in order to reduce the resistance of the transparent electrodes. Address, i.e., data electrodes are formed on the lower substrate.
The cells divided by walls are lined with phosphors. An upper dielectric layer is formed on the upper substrate to cover the transparent electrodes and the bus electrodes, and a lower dielectric layer is formed on the lower substrate to cover the address electrodes. A protection layer, generally made of magnesium oxide, is formed on the upper dielectric layer.
A related art method for forming the dielectric layers is described below.
FIGS. 1A, 1B, 1C and 1D are cross-sectional views, each showing an exemplary process for forming the dielectric layer of a related art PDP.
FIG. 1A shows a paste composition 130 containing glass powder being prepared and coated on a upper substrate 100 on which transparent electrodes (not shown) and bus electrodes 110 are formed, by a screen printing technique using a mesh 120.
Then, as shown in FIG. 1B, the coated paste composition 130 is dried and plasticized to remove organic components and sinter the glass powder, thereby forming a primary film-forming material layer 140.
Afterwards, as shown in FIG. 1C, a green sheet 150 including a secondary film-forming material layer is transferred onto the upper substrate 100 on which the primary film-forming layer 140 is formed.
Finally, as shown in FIG. 1D, the green sheet 150 is plasticized to remove organic components and sinter the glass powder, thereby forming a dielectric layer 160.
As described above, in the related art method for forming a dielectric layer 160, the dielectric layer 160 forms by transferring the green sheet 150 after coating the paste composition 130 by using a screen printing technique.
The related art manufacturing process is thus complicated, the manufacturing time is long, and the cost for manufacturing PDPs is high.
Moreover, the dielectric layer is formed by two steps, and holes or cracks may form between the primary film-forming layer 140 and the secondary film-forming layer Further, the thickness of the dielectric layer 160 cannot be uniform.